This invention relates to a method and apparatus for handling blood samples, and more particularly to a device which can be used to withdraw blood or other fluids, hold the blood or fluids while it is centrifuged to separate its components, and which can then be clamped or welded to keep the components separated during transportation.
In modern medicine, the existence of almost every disease, disorder, or condition is ordinarily determined or confirmed by analysis of a sample of blood or other fluids drawn from the patient. Very sophisticated techniques of analysis have been developed and are very effective for this purpose. Typically, in those cases wherein a patient is hospitalized, or presents himself to a well-equipped diagnostic facility, it is common for a blood sample to be taken from the patient at the direction of the physician, and for such sample to be analyzed within a short time after it is taken from the patient.
Ordinarily, a hypodermic syringe is used to pierce the skin and the tip thereof is placed in the vein or artery of the patient, a vacuum is drawn by suitable means to speed filling of the sample container, after a blood sample is taken, the container is subjected to centrifugal force to separate the red cell portion from the plasma portion of the blood. Shortly after this is done, the red blood cell portion or the plasma portion, which are separated from each other by white cells forming the so-called buffy coat, is analyzed according to known techniques. Sometimes, the serum remaining after removal of proteins from the plasma portion is also subjected to analysis. In any case, however, the analysis is ordinarily made within a short time following separation of the blood into these two principal components by centrifugal action. Accordingly, assuming proper test conditions, it is well known that analysis made immediately or very shortly after blood samples are taken is an accurate and very helpful tool for diagnostic or other purposes.
However, blood taken from a patient is, in several important respects, still "alive" in the sense that biological and chemical reactions continue to occur therein even after the blood is removed from the patient. Moreover, it is well known that reactions take place in different portions of blood samples after separation thereof, that is, a factor or characteristic of the red cell and WBC portion of a blood sample may react with a component or element of the plasma or serum portion of the blood. Whereas this condition is a normal one during the time the blood is within the body of the patient, and is not harmful per se, it is a condition which adversely affects the accuracy of blood analysis if the analysis is carried out a significant time after removal of the blood from the body of the patient.
Accordingly, in those cases wherein the patient is not presented for blood sampling to a hospital or other facility having an adequate and readily available laboratory, and wherein it is customary for the blood sample to be taken for analysis, to be centrifugally separated into red blood cell and plasma fractions, and then be stored until pick up by a representative of the laboratory wherein the tests are to be taken, the likelihood of an inaccurate analysis is increased.
Consequently, because of the "live" nature of the blood, analysis performed on blood samples of this type may be inaccurate, useless, or even misleading and perhaps dangerous when used as a diagnostic base for administering treatment to the patient whose blood is analyzed.
In order to avoid this problem a variety of specimen handling devices have been developed, see U.S. Pat. No. 3,579,303 to Pickering, U.S. Pat. No. 3,441,205 to Young, and U.S. Pat. No. 3,838,970 to Kline. These devices suffer from the disadvantage of not being capable of performing the three functions of (1) withdrawing the blood from a vein or artery, (2) holding the blood during centrifugation, and (3) keeping the component parts of the centrifuged blood separated. If the blood must be transferred to other containers before analysis, the chance of contamination is increased, and the procedure becomes more costly and inconvenient to perform. The present invention is a practical solution to many of the problems of the prior art. The present invention may be used to transfer specimens from the device to the test structures.